Data broadcast providing interactive services using digital data enables the use of convergence service of broadcasting, communication and Internet, such as Video On Demand (VOD), banking, shopping mall, video phone, as well as the viewing of existing broadcast programs.
Data broadcast can provide a variety of services by transmitting various data and applications within broadcast stream, together with video and audio. Data broadcast may be categorized into standalone service and enhanced service according to types.
That is, the standalone service (e.g., today's headline news, weather forecast, stock quoting service, traffic information, e-commerce, etc.) provides on-air broadcast programs over channels which are independently operated. The enhanced service (e.g., or introduction of synopsis or cast in drama, introduction of players or game record in sports broadcasting, etc.) provides broadcast programs and their related data together.
In order for such data broadcast, middlewares are required to enable the download and execution of the application between the application and the data broadcast receiver.
Data broadcast middlewares are classified into Advanced Common Application Platform (ACAP) (terrestrial wave), Multimedia Home Platform (MHP) (satellite), and Open Cable Application Platform (OCAP) (cable), depending on broadcast media.
The middlewares are based on Globally Executable MHP (GEM) and may include an additional API according to characteristics of media. Java-based data broadcasting application that can be executed in the middlewares are called Xlet.
Meanwhile, the application in the digital broadcast is reconfigured into a message form (DSI/DII/DDB message) according to data/object carousel scheme of Digital Storage Media Control and Command (DSMCC) and transmits the reconfigured message.
A DSMCC parser mounted on the data broadcast receiver completes the application transmitted in the message form on a module basis, and generates data broadcasting application objects through parsing.